1. Field of the Invention
The present invention relates generally to a method and apparatus for re-orienting articles as they move between an input and output portion of an article handling system. More particularly, in the preferred embodiment the present invention relates to an article handling system utilized in a printing process.
2. Description of the Prior Art
Web printing is one type of printing process that can utilize an article handling system for re-orienting articles. Web printing is a high speed process that involves printing from a continuous web(s) of paper, merging web(s), cutting the web(s), and folding the resulting cut product into individual articles known as signatures. The resulting signatures are delivered onto a moving conveyor in a lapped or shingled arrangement to create a continuous stream of signatures. With the recent advancements in technology, modem web printing can deliver an output in access of 100,000 signatures per hour. A signature can either be a finished product such as an advertisement, or a subcomponent of a larger product that in a later step will be merged and bound into a final finished product. Depending on the particular requirements of the specific signature, they may require additional finishing such as gluing, stapling, and trimming.
A typical finishing process for signatures cut from a moving web(s) is to trim three sides of the signature. Prior designers of finishing systems for web printing have generally utilized rotary knives to trim the edges of the signatures. In the prior trimming process a signature is separated from the shingled arrangement of signatures and passed through a set of rotary knives to trim two of the opposed edges of the signature. Upon the signature exiting from the rotary knives it is directed against a fixed stop which is generally known as a "bump turn" and then dropped onto a power conveyor oriented at a ninety degree angle from the trimming process. This power conveyor delivers the signature to a third rotary knife station, wherein a third edge of the signature is trimmed. Historically, this had been the generally accepted manufacturing technique to produce a finished signature, however, throughput from this type of finishing system is limited to 15,000 signatures per hour. In view of the higher speed requirements of today's web systems an output of 15,000 signatures per hour is unacceptable.
In response to the improvements in web printing systems and the associated requirement for higher throughput, engineers have developed improved rotary trimmers to allow the signatures to remain in a shingled stream and thereby increase the finishing station. Refinements to the "bump turn" are generally known in the art and are generally comprised of a combination of angles, such as 30/60 degrees and 45/45 degrees all of which together produce a 90.degree. final outcome for turning the signature.
Even with a variety of earlier designs there remains a need for an improved apparatus and method for turning and orienting articles within an article pathway. The present invention satisfies this need in a novel and unobvious way.